“ Effective brain function depends on the efficient signaling from one neuron to
the next, a lightning-fast process that depends on a quick release of
neurotransmitters at synapses. Exposure to lead during early childhood and even
later in life has long been known to affect the release of these critical
neurotransmitters. However, the precise mechanism by which lead ions (Pb2+)
impair this process has remained unknown.
A new study led by Tomás Guilarte, PhD, chair of Environmental Health Sciences
at Columbia University's Mailman School of Public Health, demonstrates that during the formation of synapses -- synaptogenesis -- exposure to lead alters the levels of several key proteins
involved in neurotransmitter release. Specifically, it produces a loss of the
proteins synaptophysin and synaptobrevin. It also increases the number of
pre-synaptic contact sites, but these sites appear to be missing these key
proteins. His work suggests that these changes are mediated by the inhibition of
the N-methyl-D-aspartate receptor (NMDAR), disrupting the release of the
trans-synaptic signaling neurotrophin, brain-derived neurotrophic factor (BDNF).
New synapses are formed throughout a healthy person's lifespan, but there is an
explosion of synapse formation during a child's early brain development. During
development, packets of preassembled proteins arrive at presynaptic active zones
(PAZ), which are highly specialized regions designed to provide fast efficient
neurotransmitter release. Disruption of this normal developmental process can
impair brain function throughout life -- as is the case with early lead exposure.
"What this work shows is that we are beginning to understand a comprehensive
mechanism by which lead exposure alters the basic molecular biology of brain
synapses. Our results are the first to explain precisely how the
vesicular release of neurotransmitters is impaired."
J. writes:
Andrew - I found her lab results. The labs were taken July 13, 2004
and she was born 10/26/2002 (so she was about 21 months old). Her
test results state 2 ug/dL with the reference range <10. It also
has a value for zinc protoporphyrin as 22 ug/dL with a reference
range of <36. Then it says CDC Risk Class 1. No evidence of excess
lead absorption. I don't know of any specific lead exposures. We
had been living in an older home (1960's) that had been updated (new
windows, fresh paint, new bathtubs I think) from the time of my
pregnancy until she was 17 months old. We then moved to another
home built in 1962 that had fresh paint but I am not sure about the
bathtub - seems older. Both homes were built over decent locations
one was a farm and one was a forest before homes were built. We do
live in a highly polluted area, close to highways, lots of tractor
trailer traffic, etc. (Columbus, OH - yuck! - sorry hope not to
offend anyone who LOVES Columbus - I just think it is too
industrial). Thanks Andrew for your interest.
my reply:
2ug/dl is not too bad but its like ten times my .2 ug/dl (my 1998 test) to give you a perspective so its signficant
when i was a teenager our drinking water was off a lead painted roof so my lead levels would have been considerably higher
10 is like drop dead toxic, only since all the kids in chicago were like 10 they waved a magic wand and said thats an ok level but in fact even 2 is to high imo
blood lead levels are a good indicator of lead, only you have to adjust down the amount that is a problem compared to the fictious reference levels
however pulse doses of lead only show in the blood for several days, then being sequestered in cells and bone and only being reflected in blood in an order of magnitude less with slow leaching
if she was bit anemic the blood lead would under-read a bit
depending on body chemistry blood lead level will vary a bit, blood lead is what has bound to iron whereas hair test lead is whats slowly mobile and binds to sulphur.
a hair test might be a better indicator of the metabolic turnover of lead
old baths that have lost their glaze in the bottom can be a suprisingly signifcant source of lead
i think the strong western cultural emphasis on dairy products comes from a need in the last three centuries to offset the chronic amounts of lead in plumbing, cosmetics etc. that used to be in daily life
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the scd diet and the original harvey-banting diet are responses to the endemic lead poisonings of those times
i really would look at my selenium protocol to help passivate the lead as it is in the bone and you have to live with it for ten years or more
of course it now looking like iodine levels have to be adequate to supplement selenium
and don't chelate, all you can do is passivate the lead and supplement minerals etc. as per my compendium and use enzymes
unusally, lead can be chelated effectively out of the blood and tissue unlike other heavy metals which cannot be targeted so specifically, but the lead levels just rebound from the bone so theres no point
lead directly displaces zinc in body biochemistry
my lead in crockery page
and
lead and scd page